Many communication systems use a fixed center frequency. For example, some wireless cellular communication systems such as 2G (CDMA) 3G (WCDMA) and 4G (WiMax, LTE) use typically fixed center frequency for communications within the cell. Sometimes all cellular networks can be operated using a single fixed center frequency (in case of frequency reuse=1).
Wired communication systems which use a fixed center frequency are known.
Frequency diversity is a well known technique in the prior art. Frequency diversity is a known method for don't-put-all-your-eggs-in-one-basket motivated communications, since any individual fixed frequency may be plagued by noise, interference and so forth. Some protocols provide a certain level of frequency diversity which may or may not be sufficient for particular applications while others provide none.
It is known that as a communication system moves from one center frequency to another, there is a transient time period which is prone to error, typically both at the transmitter end and at the receiver end, due to the “settling time” required by the hardware to adjust to the new frequency.
A variety of frequency converters are prevalent in the art.
Layer 1, 2 and 3 relays are known.
Many different communication protocols such as LTE, 3G UMTS, WiMAX, WiFi, OFDMA, CDMA and TDMA are known.
Receivers which recognize elements of a known protocol, such as cyclic prefixes, are known.
The disclosures of all publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, and of specifications of mentioned protocols are hereby incorporated by reference.